National 4B: the industrial premix hand torch for boro

The National 4B is the industrial-model premix hand torch in National’s classic blowpipe lineage — a heavier-duty member of the family aimed at borosilicate and industrial work rather than the bead-oriented 3-series. National is a long-running American hand-torch name with deep roots in scientific and industrial glasswork, and the 4B brings that simple, dependable premix character to harder glass.

What the premix flame gives you

The 4B is a premix torch: fuel and oxygen mix inside the body before reaching the flame. Premix burners are simple to light, stable, and predictable, and a premix flame runs hot — which is why it pairs naturally with hard glass like boro. For how premix compares to surface-mix designs, and where each excels, see surface mix vs premix torches; for the glass types themselves, see soft glass vs boro vs quartz.

Who the 4B is for

National markets the 4B as an industrial torch, and it suits intermediate and advanced makers doing borosilicate and industrial hand-torch work — assembly, spot heating, and localized heating where a hand-held flame is the right tool. As a hand torch it’s held and maneuvered rather than mounted; the bench vs hand torch guide covers when that mobility helps and when you’d want a bench burner. It’s less of a beginner bead torch than National’s 3-series.

Fittings, fuel, and oxygen

The 4B ships with a 1/4-inch NPT by 7-inch elbow and 9/16-18 ‘B’-size threaded hose connections (1/4-inch hose-barb by 9/16-18 adapters are standard), and uses N-4, N-6A, and P-Series tips for propane or natural gas with air. National doesn’t publish the 4B’s jet count or exact oxygen flow (LPM), so match your oxygen or air supply to the work you actually do — see how many LPM does my torch need and oxygen concentrator vs tanks.

Before you buy

Budget for the whole system, not just the torch: oxygen or compressed air, the correct propane or natural-gas regulator, flashback arrestors on both lines, the right National tip, didymium eyewear, and ventilation. New to plumbing a torch? Start with the fittings, hoses & connectors guide and the glass torch safety setup guide.

Editor’s note: spec details reflect National’s own product materials and dealer listings, including the elbow, hose fittings, and tip series above. National doesn’t publish the 4B’s jet count, exact oxygen flow (LPM), or current pricing, so confirm those specifics with National or your dealer before purchasing.